Wind turbines are generally classified by the orientation of the rotor shaft with the axis of rotation, namely, horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). For HAWTs, the main rotor shaft is set horizontally to generally align with the prevailing wind. For VAWTs, the main rotor shaft is set vertically, transverse to the prevailing wind direction. Both HAWTs and VAWTs convert the force of wind into torque of the rotating shaft.
VAWT has several advantages such as having the generator closer to the ground, easily accept changes in wind direction, and lower susceptibility to cross winds.
However, shortfalls exist with VAWTs, such as low wind efficiency and dynamic stability problems. In addition, pulsatory torque that is produced during each revolution leads to blade fatigue and may result in blades being flexed or cracked. Over time, blades may break apart and lead to catastrophic failure. Generally, current VAWTs have proven less reliable that HAWTs, particularly in this regard. In addition, VAWTs often times require relatively substantial wind as to initiate rotation of the rotor.
Moreover, current wind turbines (whether VAWTs or HAWTs) exhibit shortfalls that inhibit performance and cost effective power generation. Oftentimes, such turbines must be sized as massive structures have large rotors for large-scale power generation, requiring large moving parts to capture the wind. Such structures are ineffective in low wind environments.
It should therefore be appreciated that there remains a need for a turbine assembly that addresses these shortcomings. The present invention fulfills this need and others.